CVE-2018-6532 in Icinga
Summary
by MITRE
An issue was discovered in Icinga 2.x through 2.8.1. By sending specially crafted (authenticated and unauthenticated) requests, an attacker can exhaust a lot of memory on the server side, triggering the OOM killer.
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2018-6532 represents a critical memory exhaustion flaw within Icinga 2.x versions up to 2.8.1, exposing systems to potential denial of service conditions through resource exhaustion attacks. This issue affects both authenticated and unauthenticated attack vectors, significantly broadening its threat surface and making it particularly dangerous in production environments where Icinga 2 serves as a critical monitoring solution. The vulnerability stems from inadequate input validation and memory management within the application's request handling mechanisms, allowing attackers to craft malicious requests that trigger excessive memory consumption patterns.
The technical implementation of this vulnerability involves the exploitation of memory allocation routines within Icinga 2's web interface and API endpoints. When processing specially crafted requests, the system fails to properly validate request parameters and memory limits, leading to uncontrolled memory growth that can quickly overwhelm available system resources. This flaw operates at the application layer and leverages the fundamental design weakness in how the monitoring platform handles incoming requests, particularly those containing malformed or excessively large data payloads. The attack can be executed without requiring elevated privileges, making it accessible to any attacker who can reach the Icinga 2 service, whether through direct network access or through compromised user accounts with legitimate access rights.
The operational impact of this vulnerability extends beyond simple service disruption, as it can trigger the Linux Out-of-Memory (OOM) killer mechanism, which automatically terminates processes to prevent system crashes. This automated response can result in unintended service interruptions for legitimate monitoring activities, potentially masking actual infrastructure issues while the system attempts to recover from the memory exhaustion attack. The vulnerability's ability to affect both authenticated and unauthenticated access points means that attackers can exploit it through various attack vectors including web interface access, API calls, or even through compromised credentials, making it particularly challenging to defend against in complex network environments where multiple access points exist.
Organizations utilizing Icinga 2 versions prior to 2.8.2 should implement immediate mitigations including applying the vendor-provided security patches, implementing network-level access controls to restrict Icinga 2 service exposure, and configuring memory limits on the application hosts. Additionally, monitoring for unusual memory consumption patterns and implementing intrusion detection systems can help identify potential exploitation attempts. From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and represents a classic denial of service attack vector that can be classified under the MITRE ATT&CK framework's privilege escalation and defense evasion techniques. The vulnerability demonstrates the importance of input validation and resource management in monitoring systems, where the failure to properly constrain resource usage can lead to cascading failures that compromise the entire infrastructure monitoring capabilities.